On selecting Smartpacer on Lawnchair 14 at a glance, long pressing at a glance takes to smartpacer settings where there is no option to customise padding.
There is option of configure widget on Smartpacer separate widget.
This is the responsibility of Lawnchair, not Smartspacer. Their implementation is using the SDK, its padding and other options are not under my control.
Suggestion
On selecting Smartpacer on Lawnchair 14 at a glance, long pressing at a glance takes to smartpacer settings where there is no option to customise padding. There is option of configure widget on Smartpacer separate widget.